SiC Trench Etching with Plasma and Ion Beam Bottom Smoothing
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Solution Overview
Problem
Conventional etching processes for silicon carbide materials result in the formation of micro-trenches, which lead to local breakdown and affect the reliability and service life of power devices operating under high-voltage and high-power conditions.
Innovation Solution
An etching method involving a combination of plasma etching and ion beam etching is employed, where the first etching forms a first trench, and the second etching modifies the trench bottom to form a smooth curved shape, avoiding the formation of micro-trenches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching process is used, then etching can be completed, but micro-trenches form at the bottom of trenches causing local breakdown
Solution Approach 1:
The etching process is divided into two distinct stages: first etching to form the initial trench structure, and second etching to modify the trench bottom. This segmentation allows each stage to optimize for its specific function, preventing micro-trench formation while maintaining etching efficiency.
Solution Approach 2:
The first etching step performs preliminary trench formation, creating the basic structure before the second etching step refines the bottom surface. This preliminary action prepares the structure for the subsequent precision modification that eliminates micro-trenches.
2Reliability
If single etching method is used, then process is simple, but cannot eliminate micro-trenches completely
Solution Approach 1:
The patent combines two different etching methods (plasma etching and ion beam etching) into a unified two-step process. This merging of complementary techniques achieves complete micro-trench elimination while maintaining manageable process complexity through systematic integration.
Solution Approach 2:
The etching process uses a composite approach by applying two different etching mechanisms (plasma and ion beam) in sequence, similar to using composite materials. Each method contributes its unique advantages to achieve the overall goal of micro-trench elimination.
3Productivity
If plasma etching is used, then high etching speed is achieved, but V-shaped grooves and micro-trenches form
Solution Approach 1:
The etching process is divided into two distinct stages: first etching to form the initial trench structure, and second etching to modify the trench bottom. This segmentation allows each stage to optimize for its specific function, preventing micro-trench formation while maintaining etching efficiency.
Solution Approach 2:
The second etching step applies localized modification only to the trench bottom region, leaving the trench walls and upper portions unchanged. This local quality approach refines the bottom surface to eliminate micro-trenches without affecting the overall trench structure or requiring complete re-etching.
4Manufacturing precision
If ion beam etching is used, then precise control is achieved, but etching speed is reduced
Solution Approach 1:
The ion beam etching is applied partially, only to the trench bottom region that requires precision modification, rather than etching the entire trench. This partial action achieves the necessary precision for eliminating micro-trenches while minimizing the time spent on low-priority areas, thus maintaining overall productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method improves device performance by eliminating structural defects, reducing on-state resistance, and enhancing the current handling capability and service life of silicon carbide devices.
Implementation Method 1
One of the first etching and the second etching is plasma etching
Implementation Method 2
the other is ion beam etching
Data Source
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AI summary
Provided in the present application are an etching method and an etching system. The method comprises: providing a structure to be etched, wherein said structure is covered with a patterned mask layer; carrying out first etching on said structure by taking the mask layer as a mask, so as to form a first trench; and then carrying out second etching on the first trench by taking the mask layer as the mask, wherein one of the first etching and the second etching is plasma etching, and the other is ion beam etching, so as to carry out bottom surface modification on the first trench to obtain a second trench. In this way, the ion beam etching is carried out after the plasma etching, or the plasma etching is carried out after the ion beam etching; the first trench can be modified by means of a process different from a process for forming the first trench, so as to form a round and smooth trench bottom, thereby avoiding the formation of micro-trenches, overcoming structural defects caused during machining and manufacturing of trench devices, and improving the performance of the devices.